高级IPC DBus

# 根元素
<busconfig>

  <!-- 根据指定的 -system或 -session 来选择的配置文件 -->
  <type>system</type>

  <!-- dbus-daemon运行的用户 -->
  <user>dbus</user>

  <!-- Fork into daemon mode -->
  <fork/>

  <!-- We use system service launching using a helper -->
  <standard_system_servicedirs/>

  <!-- This is a setuid helper that is used to launch system services -->
  <servicehelper>//usr/libexec/dbus-1/dbus-daemon-launch-helper</servicehelper>

  <!-- Write a pid file -->
  <pidfile>/run/dbus/messagebus.pid</pidfile>

  <!-- Enable logging to syslog -->
  <syslog/>

  <!-- 指定授权机制。如果不存在，所有的机制都被允许。 -->
  <auth>EXTERNAL</auth>

  <!-- 总线监听的地址，支持unix socket，tcp，system等
        -->
  <listen>unix:path=/run/dbus/system_bus_socket</listen>
  <listen>unix:path=/tmp/foo</listen>
  <listen>tcp:host=localhost,port=1234</listen>  


  <policy context="default">
    <!-- All users can connect to system bus -->
    <allow user="*"/>

    <!-- Holes must be punched in service configuration files for
         name ownership and sending method calls -->
    <deny own="*"/>
    <deny send_type="method_call"/>

    <!-- Signals and reply messages (method returns, errors) are allowed
         by efault -->
    <allow send_type="signal"/>
    <allow send_requested_reply="true" send_type="method_return"/>
    <allow send_requested_reply="true" send_type="error"/>

    <!-- All messages may be received by default -->
    <allow receive_type="method_call"/>
    <allow receive_type="method_return"/>
    <allow receive_type="error"/>
    <allow receive_type="signal"/>

    <!-- Allow anyone to talk to the message bus -->
    <allow send_destination="org.freedesktop.DBus"
           send_interface="org.freedesktop.DBus" />
    <allow send_destination="org.fedoraproject.FirewallD1" 
    send_interface="org.fedorapproject.FirewallD1" />
    <allow send_destination="org.freedesktop.DBus"
           send_interface="org.freedesktop.DBus.Introspectable"/>
    <!-- But disallow some specific bus services -->
    <deny send_destination="org.freedesktop.DBus"
          send_interface="org.freedesktop.DBus"
          send_member="UpdateActivationEnvironment"/>
    <deny send_destination="org.freedesktop.DBus"
          send_interface="org.freedesktop.DBus.Debug.Stats"/>
    <deny send_destination="org.freedesktop.DBus"
          send_interface="org.freedesktop.systemd1.Activator"/>
  </policy>

  <!-- Only systemd, which runs as root, may report activation failures. -->
  <policy user="root">
    <allow send_destination="org.freedesktop.DBus"
           send_interface="org.freedesktop.systemd1.Activator"/>
  </policy>

  <!-- root may monitor the system bus. -->
  <policy user="root">
    <allow send_destination="org.freedesktop.DBus"
           send_interface="org.freedesktop.DBus.Monitoring"/>
  </policy>

  <!-- If the Stats interface was enabled at compile-time, root may use it.
       Copy this into system.local.conf or system.d/*.conf if you want to
       enable other privileged users to view statistics and debug info -->
  <policy user="root">
    <allow send_destination="org.freedesktop.DBus"
           send_interface="org.freedesktop.DBus.Debug.Stats"/>
  </policy>

  <!-- Include legacy configuration location -->
  <include ignore_missing="yes">/etc/dbus-1/system.conf</include>

  <!-- 包含的子配置文件. -->
  <includedir>system.d</includedir>

  <includedir>/etc/dbus-1/system.d</includedir>

  <!-- This is included last so local configuration can override what's 
       in this standard file -->
  <include ignore_missing="yes">/etc/dbus-1/system-local.conf</include>

  <include if_selinux_enabled="yes" selinux_root_relative="yes">contexts/dbus_contexts</include>

</busconfig>

dbus-send --session \
--dest=org.freedesktop.DBus \
--type=method_call \
--print-reply \
/org/freedesktop/DBus \
org.freedesktop.DBus.ListNames

method return time=1631452206.288425 sender=org.freedesktop.DBus -> destination=:1.29 serial=3 reply_serial=2
   array [
      string "org.freedesktop.DBus"
      string "org.freedesktop.login1"
      string "org.freedesktop.systemd1"
      string "org.fedoraproject.FirewallD1"
      string "org.freedesktop.PolicyKit1"
      string ":1.17"
      string ":1.0"
      string ":1.29"
      string ":1.18"
      string ":1.1"
   ]

dbus-send --session \
--dest=org.freedesktop.DBus \
--type=method_call \
--print-reply \
/org/freedesktop/DBus \
org.freedesktop.DBus.Introspectable.Introspect

# cat /usr/lib/systemd/system/firewalld.service 
[Unit]
Description=firewalld - dynamic firewall daemon
Before=network.target
Before=libvirtd.service
Before=NetworkManager.service
Conflicts=iptables.service ip6tables.service ebtables.service

[Service]
EnvironmentFile=-/etc/sysconfig/firewalld
ExecStart=/usr/sbin/firewalld --nofork --nopid $FIREWALLD_ARGS
ExecReload=/bin/kill -HUP $MAINPID
# supress to log debug and error output also to /var/log/messages
StandardOutput=null
StandardError=null
Type=dbus
BusName=org.fedoraproject.FirewallD1

[Install]
WantedBy=basic.target
Alias=dbus-org.fedoraproject.FirewallD1.service

dbus-send --system --dest=org.freedesktop.DBus --type=method_call --print-reply \
/org/freedesktop/DBus org.freedesktop.DBus.ListNames | grep FirewallD

dbus-send --system --dest=org.fedoraproject.FirewallD1 --print-reply \
/org/fedoraproject/FirewallD1 org.freedesktop.DBus.Introspectable.Introspect

firewall-cmd --get-zones

dbus-send --system \
--dest=org.fedoraproject.FirewallD1 \
--print-reply \
--type=method_call /org/fedoraproject/FirewallD1 \
org.fedoraproject.FirewallD1.zone.getZones

# firewall-cmd --zone=public --list-all

dbus-send --system --dest=org.fedoraproject.FirewallD1 --print-reply --type=method_call \
/org/fedoraproject/FirewallD1 org.fedoraproject.FirewallD1.getZoneSettings string:"public"